1. Field of the Invention
The present invention relates to an optical fiber connector, and particularly relates to an optical fiber connector for light coupling.
2. Background of the Invention
With optical fiber communication developing, requirements for optical fiber connectors are increased. Each optical fiber connector always works with an optoelectronic component, and an entrance of the optical fiber connector must be completely enclosed to prevent dust and other external objects from affecting optical signals and to protect users' eyes from light emitted by the optical fiber connector.
With respect to FIG. 1, a dust-proof bung 12a is removable from a first conventional optical fiber connector 1a to mate with an optical fiber coupling. When the first conventional optical fiber connector 1a isn't in use, the dust-proof bung 12a is inserted into an optical-fiber insertion hole of the first conventional optical fiber connector 1a, thereby to prevent dust and other external objects from affecting optical signals. However, the dust-proof bung 12a must be manually inserted and removed, and should be stored well in order to avoid getting lost. Obviously, the dust-proof bung 12a presents a potential hazard of making children choked if not carefully stored. On the other hand, if the first conventional optical fiber connector 1a is packaged with an electronic apparatus, this assembly requires a testing procedure before shipping. During the testing producer, the dust-proof bung 12a in the packaged assembly is supposed to be removed first, the electronic apparatus is then probed to check functions and characteristics, and then, the dust-proof bung 12a is put back on the housing 11a thereof. The manufacturing steps are so complex to waste time and labor.
Referring to FIGS. 2A and 2B, a second conventional optical fiber connector 2a is open by a lateral side thereof. The second conventional optical fiber connector 2a includes a housing 21a, a supporting spring 23a, and a shuttle 24a. The supporting spring 23a has two ends respectively abutting against a rear surface of the shuttle 24a and an inner side of the housing 21a. The shuttle 24a includes a shaft 22a connected to the housing 21a by a fixed bracket, and the shaft 22a rotates freely and inwardly in order to accept an optical fiber coupling 6a. When the optical fiber coupling 6a is removed from the second conventional optical fiber connector 2a, the supporting spring 23a, which is pressed when the optical fiber coupling 6a is inserted, will release its recovery force to push the shuttle 24a back to enclose the second conventional optical fiber connector 2a. 
Generally speaking, the optical fiber coupling 6a usually includes two opposite semi-circular strips protruding from a peripheral thereof for guiding in and mating with at least one guiding groove of the conventional fiber optical connectors. The guiding groove of the second conventional optical fiber connector 2a is formed on a front surface of the shuttle 24a, in order to guide each one of the semi-circular strips of the optical fiber coupling 6a. However, the shuttle 24a connects the fixed bracket via the shaft 22a in advance, and further connects the housing 21a and the supporting spring 23a via the fixed bracket. Therefore, the shuttle 24a is not stable enough to provide a long service life due to tolerances existed between the shuttle 24a, the shaft 22a, the fixed bracket and the housing 21a. In addition, the second conventional optical fiber connector 2a further includes a baffle 25a arranged behind the shuttle 24a to limit an insertion depth of the optical fiber coupling 6a. Because the baffle 25a restricts only single one of the two opposite semi-circular strips, the optical fiber coupling 6a is secured insufficiently to reduce the secure capacity of the second conventional optical fiber connector 2a. 
Illustrated in FIGS. 3A and 3B, a third conventional optical fiber connector 3a is open by a topside thereof. The third conventional optical fiber connector 3a includes a housing 31a, a shaft 32a assembled on the housing 31a, a pair of bracket springs 33a and a shuttle 34a covering an entrance of the housing 31a. Each of the bracket springs 33a has two ends, one connects to a rear surface of the shuttle 34a, and the other one connects an inner top surface of the housing 31a, so that the shuttle 34a can rotate inwardly due to the bracket springs 33a. The optical fiber coupling 6a can be inserted in the third optical fiber connector 3a. The shuttle 34a rotates about the shaft 32a to retain against the inner top surface of the housing 31a, when the optical fiber coupling 6a is inserted. Then the shuttles 34a is restored back to its original status by a resilient force thereof, when the optical fiber coupling 6a is removed.
However, the process of inserting the optical fiber coupling 6a may damage the shaft 32a because the shaft 32a endures the weight of the shuttle 34a. To avoid such damages, the shaft 32a should be made of metallic materials, which is stronger and accordingly more expensive than the prior art. The metallic shaft 32a has a spring 33a penetrating through the topside thereof to connect the shuttle 34a. Thus, the third conventional optical fiber connector 3a fails to reduce costs and manufacturing steps.
FIG. 4 shows a fourth conventional optical fiber connector 4a that is open by a topside thereof. The fourth conventional optical fiber connector 4a includes a housing 41a, a spring plate 43, and a shuttle 44a having a shaft 42a. The fourth conventional optical fiber connector 4a has a shortcoming, like the third conventional optical fiber connector 3a, to be overcome. The shaft 42a cannot endure the load, and the service life of the fourth conventional optical fiber connector 4a decreases thereby.
Referring to FIG. 5, a fifth conventional optical fiber connector 5a is open by a bottom side thereof. The fifth conventional optical fiber connector 5a includes a housing 51a and a shuttle 54a extending downwardly from the housing 51a. The shuttle 54a is made of resilient material, in order to bend inwardly. The shuttle 54a can rotate due to the insertion of the optical fiber coupling 6a, and release a resilient force to return when the optical fiber coupling 6a is removed. The housing 51a, as a usual type, has a guiding recess formed on an inner bottom surface in advance; the shuttle 54a encloses an entrance and the guiding recess of the housing 51a simultaneously. For ease to guide the optical fiber coupling 6a, the shuttle 54a includes a substitution guiding recess formed on a front surface to replace the guiding recess the housing 51a. The substitution guiding recess extends from a bottom end to approach a top end of the shuttle 54a, but fails to reach a rear end of the housing 51. Because the shuttle 54a is movable relative to the housing 5a, and only the substitution guiding recess of the shuttle 54 is provided to guide the optical fiber coupling 6a, the connection between the optical fiber coupling 6a and the conventional optical fiber connector 5a lacks stability and accuracy. Furthermore, the resilient shuttle 54a is bent with such frequency to lose flexibility, so that the shuttle 54a eventually cannot recover.
Moreover, the third, the fourth, and the fifth conventional optical fiber connector 3a, 4a, 5a cannot restrict the insertion depth of the optical fiber coupling 6a, and this may results in the optical fiber coupling 6a rubbing against and scraping a surface of the optoelectronic component, so as to reduce or affect the optical signal therefrom.
Hence, an improvement over the prior art is required to overcome the disadvantages thereof.